<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<script>

    console.log('true') //false

    let a='';

    console.log(Boolean(a))  //false
    console.log(Boolean(11))
    console.log(Boolean('li'))
    console.log(Boolean(null)) //false
    console.log(Boolean(undefined))
    if(a){
        console.log('true') //true
    }


    const b=[1,2,3]


    let c=JSON.stringify(b)
    console.log(JSON.stringify(b));     //返回 '[1,2,3]'

    console.log(typeof c)
</script>
</body>
</html>